Ajuste do modelo matemático de uma aeronave com sistema de aumento de estabilidade com base em ensaios em túnel de vento
Mattos, Wellington da Silva (2007). Adjustment of an Aircraft Mathematical Model with Stability Augmentation System based on Wind Tunnel Analysis. M.Sc. Dissertation -Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, 2007. The present work describes the application of a model updating method, based on experimental wind tunnel data to an aircraft longitudinal stability augmentation system (LSAS). The study includes a revision of model updating methods, the development of
... the aircraft mathematical model and the description of a, previously conducted, aircraft LSAS wind tunnel testing. The LSAS is comprised by (1) A data acquisition system, which processes the sensor signal and sends the control command to the actuator; (2) A potentiometer, used as a pitch angle sensor; and (3) A servo motor, used to actuate canard deflection. The aircraft model is based on the Grumman X-29, which has canard and forward swept wing. Its static stability margin can be adjusted by changing the center of rotation position which, in turn, coincides with the aircraft center of gravity position through weight balance. The airplane mathematical model updating is carried out, in the Matlab/Simulink environment, by adjusting model parameters for aircraft stability derivatives, digital filter, sensor and servo dynamics. The objective is to obtain an optimal correlation between numerical and experimental results. The parametric sensitivity analysis method is chosen for model updating. In a first phase of the study the comparison between theoretical and experimental results is based on frequencies and damping ratios for aircraft pitch angle response to an impulse canard deflection input. In a second phase the comparison is based directly on experimental and numerical pitch angle time response to the same impulse canard deflection input. Three center of gravity positions are analyzed, one for which the aircraft is statically stable and two for which it is unstable. Results show large variations among adjusted parameters indicating the need for improvements in the implementation of the adopted methodology.